Turkish Journal of Physiotherapy and Rehabilitation; 32(3) ISSN 2651-4451 | e-ISSN 2651-446X www.turkjphysiotherrehabil.org 2546 CEPHALOMETRIC FLOATING NORMS FOR THE BETA ANGLE, MAXILLARY-MANDIBULAR PLANE ANGLE BISECTOR-WITS AND YEN- LINEAR AMONG THE CHENNAI POPULATION : A RETROSPECTIVE - IN- VITRO STUDY Dr. Vineeth Kumar 1 , Dr. Dhivya Dilipkumar MDS 2 , Dr. Deepak. C MDS , PhD 3 , Dr. Akshay Tandon MDS 4 , 1 PG Student, 2 Associate Professor, 3 Professor and Head, 4 Senior lecturer 1,2,3,4 Department of Orthodontics, SRM Dental college, Kattankulathur, SRM Institute of science and technology SRM Nagar, Kattankulathur, Kanchipuram Chennai , TN , India 1 vineeth.kumar93@gmail.com, 2 dhiv2000@yahoo.com, 3 deepakc@srmist.edu.in, 4 aks226mpl@gmail.com ABSTRACT: Aim: The aim of the study was to provide floating norms for the Beta angle, MMBP-Wits and YEN-Linear in adult Chennai population that can help in proper diagnosis and treatment planning of different cases. Materials and methodology: Lateral cephalometric radiographs of 100 subjects (50 males and 50 females; mean age, 18-25 years) were taken from the record room of the college (Department of Orthodontics and Dentofacial Orthopedics, SRM Kattankulathur Dental College and Hospital). The lateral cephalograms were traced for The Beta angle, MMBP-Wits and YEN-Linear. Lateral cephalometric head film was obtained with the patient positioned in Natural Head Position, seated condyle and with passive lips. The cephalograms were further traced by the same operator; this comprised the cephalometric database for the study. The final results obtained were compared between Males and Females of the study to verify the acceptable standards of them. Results: The outcomes of the current study presented there to be no statistically significant difference between gender in the YEN-Linear, Beta angle and MMBP-Wits for the Chennai population. Hence a common normative range applicable for both the genders was proposed. Conclusion: “There was no Statistically Significant gender wise difference among the subjects of the Chennai population. Hence a common normative range applicable for both the genders can be proposed. Floating norms have been provided to individualize the reference values for The Beta angle, MMBP-Wits and YEN-Linear. Keywords: Beta angle, Floating norms, MMBP-wits, YEN-Linear. I. INTRODUCTION Lateral cephalometric radiography was introduced by Holly Broadbent (USA) and Herbert Hofrath (Germany) in 1931. Since the introduction of lateral cephalometric radiography,it is considered as the ‘Gold’ standard tool in orthodontic diagnosis and the treatment planning. Transverse, sagittal and vertical are the three most commonly used planes of divergences in orthodontics. Among them, the sagittal discrepancies are most frequently encountered in day-to-day practice 1 . ANB angle, introduced by Riedel was used to express the apical base relationship 3 . Jacobson in 1975 revealed that the ANB angle did not give a correct evaluation of the changes in the Skeletal relationship since the mandible’s growth rotation as well as antero-posterior location of the Nasion in relation to the points A and B could in turn result in alteration of the ANB angle. Jacobson had introduced The Wits Appraisal with an intention to solve the issues associated with ANB angle 4 . Nevertheless, Wits Appraisal suffers limits associated with the identification and the cant of the occlusal plane